I host a SMP server on a VPS and lately there's been a couple of hard crashes at the hosting facility which has caused some interesting biome glitches.

The initial spawn area and the surrounding blocks were forest/rainforest when the world was first created. Also I claimed a rainforest island and started working on it, putting easily 60 hours into developing it so far.

However, because of the crashes, it seems that the biomes are glitched. Now instead of being a nice lush rainforest, I'm living in TUNDRA. I even checked with the biome checking plugin for bukkit and it seems that the biome for my island has totally switched.

My question is, how can I fix this? Is there a bukkit plugin or some kind of editor that I can use?

2 Answers
2

One possible reason could be data corruption. The Random Seed of each map is saved in the file, and this seed determines how the world looks. Due to data corruption during the crashes it could be that this seed has changed, which would effectively screw everything (but would deliver interesting results for sure).

Another possible explanation is that you either got a completely new map1 or chunks got corrupted/replaced/lost.

Anyway, my best advice is to restore from backup. Even if you change the seed back (given that you know the original one) or find the corrupted chunks, there's not much to gain. Parts of the world are already corrupted and you could only remove them and let them regenerate.

Based on what I've seen, there's definitely new chunks in different places, but nothing global. The terrain is the same except in just a few areas, but it's VERY white. I guess I'll just tell my friends that they'll have to live with the new snowy areas or move. =/
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Kenneth PoseyMay 22 '11 at 20:22

@Kort Pleco: Is the world available for download?
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BobbyMay 22 '11 at 20:25

I keep server backups, it was just three days before I figured out that it wasn't a random snowfall and it was actually a complete biome shift. I know I've done a ton of work then and others have too, so we'll likely not want to change. Bobby yes it is available but it's pushing 120mb right now, lol.
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Kenneth PoseyMay 23 '11 at 1:26

@Kort Pleco: If you have regular backups then you can check if the Seed has changed or not. If the Seed is still the same, then there's corruption somewhere else.
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BobbyMay 23 '11 at 20:26

I'm hosting a SMP server and also had big problems with moving biomes and spawn points. When exploring new areas the map also got "sliced", where you had massive completeley straight walls where different terrains met.

As @Bobby hinted, this was all caused by a corrupted seed and here's how I solved it.

What you need:

The original seed. (For this you need an old uncorrupted save and Loledit, see below)

Open the old save file in Loledit and get the original seed. For me on Windows7 Loledit shows an error message when starting, but I just press continue.

Open the corrupted save in Loledit and set the original seed.

Biomes are now back to their original layout.

Now the seed problem is fixed so the biomes should be back to normal and any new areas explored will be ok. All areas explored while the seed was corrupted are still broken and will result in the dreaded "sliced walls". This can be fixed with MCEdit if you don't mind losing any buildings in the corrupted sectors.

First you need to know which areas are corrupted. You can see it in MCEdit but I found it easier to generate an overview map with MCMap. The areas that are based on the corrupted seed stand out quite well and should be easily spotted in the generated map.

Open the corrupted save in MCEdit. The controls take some getting used to but are well documented. "Q" for flying up to get a good overview, then WASD to move around, right mouse button to move camera.

First use the select tool (leftmost button in button bar) to select any corrupted area, then press "select chunks" to snap the selection to chunks.

With the selection still active, go to chunk control (rightmost button) and press "delete". Rinse and repeat, select/delete all corrupted areas.

Areas are deleted as soon as you press delete so no saving is needed. You can also use MCEdit to reset the bugged spawn point to anywhere you like. Quit MCEdit before opening the save anywhere else!!!

Load the fixed save game as a single player map since it seems some data must be regenerated. After that you can open it again in Loledit to verify that the seed is still correct.

Asker mentioned he didn't want to lose the work that was done by players, and if I'm understanding correctly, this method would delete that work.
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ArkiveJul 8 '11 at 20:58

Not necessarily. In a normal case I would say that corrupted parts that need deleting usually are at the edge of the explored world, while buildings are clustered in areas that was explored relatively early before the seed got corrupted. But true, if you have a big player base that run all over the place some work might be lost. But then there is really no good way of fixing it since the buildings are in corrupted areas. Also note that you don't need to delete any chunks if you just want to fix the glitched biomes.
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OmokoiiJul 8 '11 at 21:33

Ah, that's the clarification I needed. I thought you had to delete the chunk and let it regenerate with the new seed.
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ArkiveJul 9 '11 at 5:43